Back at the start of World War Two the authorities forbade the use of the Underground as an air raid shelter. Instead Londoners were supposed to rely on hastily built neighborhood shelters or on the famous Anderson shelters, which were basically rabbit hutches made from corrugated iron with some earth shoveled on top. Londoners being Londoners, the prohibition on using the Underground lasted right up until the first air raid warning, at which point the poorly educated but far from stupid populace of the capital did a quick back-of-the-envelope comparison between the stopping power of ten meters of earth and concrete and a few centimeters of compost, and moved underground en masse. The authorities were appalled. They tried exhortation, persuasion, and the outright use of force, but the Londoners wouldn't budge. In fact, they started to organize their own bedding and refreshment services.